Hearing aids are devices used to detect, process, and amplify sound, and then transmit the detected sound to a user. Hearing aids therefore include electrical components, including a processor for analyzing and amplifying detected signals, a power source, a microphone, and a receiver. The microphone detects sound waves and creates electrical signals indicative of the detected sound waves. The electrical signals are typically processed within a processor where desirable aspects of the detected signals may be amplified, and the processed signals are then passed to the receiver. The receiver generally includes a movable membrane for generating pressure waves (i.e. sound waves) that are directed toward the ear drum of the user of the hearing aid.
Hearing aids have been developed that can be worn in more than one configuration. Some hearing aids include electrical components to be worn behind the ear, and components interior to the ear canal, with fluid connections between the interior components and the components worn behind the ear. Receiver In Canal (RIC) hearing aids are hearing aids where the electrical components required to detect, analyze, amplify, and transmit sound waves to the user are fully contained within the ear canal. For example, U.S. Pat. No. 7,227,968 discloses a device adapted for fitting an acoustic receiver within a bony portion of the ear canal using an expansible balloon-like device to seat the acoustic receiver within the bony portion of the ear canal and thereby enhance the transmission of sound waves and enhance the comfort experienced by a user.
Hearing aids today are typically assembled in one piece such that all the components—are encapsulated in a common plastic shell. The hearing aid is positioned at a relatively large distance from the eardrum, usually in front of the bony area of the ear canal. The reason for this is that the plastic material forming the shell encapsulating the above-mentioned components is hard, which makes it difficult to position such a hearing aid in the bony area of the ear canal without introducing pain to the user of the hearing aid. Another disadvantages of one-piece hearing aids include the large distance between the receiver output and the eardrum to be excited, acoustic feedback from the receiver to the microphone, vibrations of the receiver (which is transmitted to the ear canal and can be unpleasant for the user), a somewhat complicated and painful mounting of the hearing aid.